Codium Structure
and Reproduction

Codium fragile is 10 to 30 centimeters tall with several erect
branches from a broad basal disk. The "fingers" are branched
and as thick as a pencil or finger. The branches float in the water when
covered and hang down when the tide is out. Under a microscope, one can
see that each "finger" is made up of many fine filaments woven
together. On the outside, the filaments give rise to swollen utricles.
These utricles are club-shaped, ending in a point. They are full of photosynthetic
chloroplasts. Epiphytic red algae often grow on the tips of the utricles:

Unlike many algae and other plants, Codium has only a gametophyte
generation. The eggs and sperm are found in separate chambers called
gametangia which project off the utricles:

Most species of Codium are dioecious, with the male and female
gametangia on separate plants. Each of the gametes has two flagella,
and the female gametes are larger than the male gametes.